Bacillus ciccensis sp. nov., isolated from maize (Zea mays L.) seeds

Proposal of Bacillus ciccensis Liu et al. as a Later Heterotypic Synonym of Cytobacillus solani (Liu et al.) Patel and Gupta Using Comparative Genomic Analysis

Bacillus ciccensis and Cytobacillus solani were reported to belong to separate genomic species based on a polyphasic taxonomic approach. However, we found that type strains of B. ciccensis and C. solani should belong to the same genomic species based on the clustering patterns resulting from genome phylogenetic analysis. The average nucleotide identity and digital DNA-DNA hybridization values between the genomes of two type strains were 99.6% and 96.9%, respectively, much higher than 95 ~ 96% and 70% cut-off point proposed and generally accepted species boundary. This result was also supported by a comprehensive comparison of phenotypic characteristics between the two type strains. These results suggested that B. ciccensis and C. solani had the same taxonomic position. Consequently, we propose that B. ciccensis is a later heterotypic synonym of C. solani.

Robust demarcation of 17 distinct Bacillus species clades, proposed as novel Bacillaceae genera, by phylogenomics and comparative genomic analyses: description of Robertmurraya kyonggiensis sp. nov. and proposal for an emended genus Bacillus limiting it only to the members of the Subtilis and Cereus clades of species

To clarify the evolutionary relationships and classification of Bacillus species, comprehensive phylogenomic and comparative analyses were performed on >300 Bacillus/Bacillaceae genomes. Multiple genomic-scale phylogenetic trees were initially reconstructed to identify different monophyletic clades of Bacillus species. In parallel, detailed analyses were performed on protein sequences of genomes to identify conserved signature indels (CSIs) that are specific for each of the identified clades. We show that in different reconstructed trees, most of the Bacillus species, in addition to the Subtilis and Cereus clades, consistently formed 17 novel distinct clades. Additionally, some Bacillus species reliably grouped with the genera Alkalicoccus, Caldalkalibacillus, Caldibacillus, Salibacterium and Salisediminibacterium. The distinctness of identified Bacillus species clades is independently strongly supported by 128 identified CSIs which are unique characteristics of these clades, providing reliable means for their demarcation. Based on the strong phylogenetic and molecular evidence, we are proposing that these 17 Bacillus species clades should be recognized as novel genera, with the names Alteribacter gen. nov., Ectobacillus gen. nov., Evansella gen. nov., Ferdinandcohnia gen. nov., Gottfriedia gen. nov., Heyndrickxia gen. nov., Lederbergia gen. nov., Litchfieldia gen. nov., Margalitia gen. nov., Niallia gen. nov., Priestia gen. nov., Robertmurraya gen. nov., Rossellomorea gen. nov., Schinkia gen. nov., Siminovitchia gen. nov., Sutcliffiella gen. nov. and Weizmannia gen. nov. We also propose to transfer 'Bacillus kyonggiensis' to Robertmurraya kyonggiensis sp. nov. (type strain: NB22=JCM 17569^T=DSM 26768). Additionally, we report 31 CSIs that are unique characteristics of either the members of the Subtilis clade (containing the type species B. subtilis) or the Cereus clade (containing B. anthracis and B. cereus). As most Bacillus species which are not part of these two clades can now be assigned to other genera, we are proposing an emended description of the genus Bacillus to restrict it to only the members of the Subtilis and Cereus clades.

Bacillus dafuensis sp. Nov., Isolated from a Forest Soil in China

A Gram-staining-positive, motile, rod-shaped, aerobic bacterial strain FJAT-25496 ^T was isolated from a forest soil sample collected from Dafu County, Chengdu City, Sichuan Province, China. Strain FJAT-25496 ^T grew at 15-50 °C (optimum 35 °C), pH 6.0-10.0 (optimum 8.0), and NaCl tolerance of 0-4.0% (w/v) (optimum 0%). The strain contained iso-C_15:0 and anteiso-C_15:0 as the predominant cellular fatty acids as well as MK-7 as the only menaquinone. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidyl glycerol (PG). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FJAT-25496 ^T was a member of the genus Bacillus, and most closely related to Bacillus solani FJAT-18043 ^T (97.8%), Bacillus praedii FJAT-25547 ^T (97.8%), Bacillus depressus BZ1^T (97.7%), Bacillus oceanisediminis H2^T (97.7%), and Bacillus ciccensis 5L6^T (97.6%). Based on complete genome comparisons between strain FJAT-25496 ^T and the type strains of its closely related species, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 73.4-76.3% and 21.7-23.2%, respectively. The genomic DNA G + C content of strain FJAT-25496 ^T was 36.9%. On the basis of phenotypic, phylogenetic, chemotaxonomic, and genomic features, strain FJAT-25496 ^T is considered to represent a novel species of the genus Bacillus, for which the name Bacillus dafuensis sp. nov. is proposed. The type strain is FJAT-25496 ^T (= CCTCC AB 2019182 ^T = KCTC 43120 ^T).

Investigating the endophytic bacterial diversity and community structures in seeds of genetically related maize (Zea mays L.) genotypes

This research aimed to investigate the composition and diversity of endophytic bacterial community in seeds of four hybrid maize and their parental lines, which was used to reveal the potential relationship and association of endophytic bacteria between maize genotypes and their genetic relevance. High-throughput sequencing (HTS) technology showed that a total of 1419 OTUs (46.6%) were parental lines unique and 1052 OTUs (34.5%) were hybrid varieties unique, with only 575 core OTUs revealed in all the samples. Most OTUs belonged to Proteobacteria. Enterobacter (23.2%), Shigella (21.2%), Pseudomonas (15.8%) and Achromobacter (10.1%) were the major genera; the bacterial community composition and diversity of endophytic bacteria were inconsistent among different seed genotypes. Based on principal component analysis (PCA), the results referred that the endophytic composition of hybrid sample showed obvious correlation with their female parental lines, and in 'Jingke968' and 'MC738' with the same female line the endophytic community was more similar than other hybrid samples. This was the first ever use of HTS technology for investigating the endophytic bacterial diversity and community structures in seeds of genetically related maize genotypes, it was shown that, there were core microbes shared among all genotypes of seed samples, and the female parental line was more significant to impact on the composition of their hybrid seeds than male parental line. This study would provide scientific clues for the future research on the vertical transmission of endophytes among maize generations.

Complete genome sequence of Bacillus ciccensis 5L6T, a new species isolated from maize (Zea mays L.) seeds with anti-fungal activity

Maize is a crop grown worldwide. Bacillus ciccensis 5L6^T was isolated from maize (Zea mays L., Jingke968) seeds and was a new species of Bacillus with potential anti-fungal activity. The complete genome of 5L6^T was sequenced and assembled with a length of 5,207,802 bp and a GC content of 37.42%. The proteins responsible for anti-fungal activity and the potential beneficial interaction with maize of 5L6^Twere annotated and reported here. The complete genome sequence of the new species B. ciccensis 5L6^T will promote its biological application.